In the field of mobile communications, so-called “drive testing” is a technique of choice used by network operators to determine the performance of a so-called “home” network. Drive testing involves sending road-vehicles into cell coverage areas of networks to test, inter alia signal strength. Typically, the road-vehicles are equipped with costly and bulky equipment, which is used to test the signal strength and provide other metrics. Indeed, drive testing is a procedure that is labour-intensive and not particularly comprehensive. In this respect, a Radio Frequency (RF) field is undersampled in time, since each sample covers only a fraction of a second per month at any one location. Another disadvantage of drive testing is that the RF field is also undersampled in space, since most major roads are not driven their entire length and only some of the minor roads are driven. Consequently, drive testing misses all locations without a road, for example parks, stadiums, homes, offices, and/or conference centres. Omission of testing in such areas is disadvantageous as users of communications terminals are likely to be located in such areas. Likewise, users are less likely to reside in some other areas covered by a given drive test. Further, users of mobile communications terminals are known to “roam” from the home network to a so-called “foreign” or “visited” network. The visited network need not necessarily be located in a different country to the home network; it can be a network of a partner network operator and located in the same country as the home network. Additionally, irrespective of the location on the globe of a given mobile communications terminal, it is desirable for network operators to possess information concerning performance of a given network in which the given mobile communications terminal is located when used. However, an operator of the home network is not usually privy to such information in relation to the visited networks.